1 files changed, 59 insertions, 11 deletions

diff --git a/src/core/lib/gprpp/ref_counted_ptr.h b/src/core/lib/gprpp/ref_counted_ptr.h
index 534d3d03cb..91ca8eae63 100644
--- a/src/core/lib/gprpp/ref_counted_ptr.h
+++ b/src/core/lib/gprpp/ref_counted_ptr.h
@@ -36,7 +36,10 @@ class RefCountedPtr {
   RefCountedPtr(std::nullptr_t) {}
 
   // If value is non-null, we take ownership of a ref to it.
-  explicit RefCountedPtr(T* value) { value_ = value; }
+  template <typename Y>
+  explicit RefCountedPtr(Y* value) {
+    value_ = value;
+  }
 
   // Move support.
   RefCountedPtr(RefCountedPtr&& other) {
@@ -49,6 +52,18 @@ class RefCountedPtr {
     other.value_ = nullptr;
     return *this;
   }
+  template <typename Y>
+  RefCountedPtr(RefCountedPtr<Y>&& other) {
+    value_ = other.value_;
+    other.value_ = nullptr;
+  }
+  template <typename Y>
+  RefCountedPtr& operator=(RefCountedPtr<Y>&& other) {
+    if (value_ != nullptr) value_->Unref();
+    value_ = other.value_;
+    other.value_ = nullptr;
+    return *this;
+  }
 
   // Copy support.
   RefCountedPtr(const RefCountedPtr& other) {
@@ -63,17 +78,37 @@ class RefCountedPtr {
     value_ = other.value_;
     return *this;
   }
+  template <typename Y>
+  RefCountedPtr(const RefCountedPtr<Y>& other) {
+    if (other.value_ != nullptr) other.value_->IncrementRefCount();
+    value_ = other.value_;
+  }
+  template <typename Y>
+  RefCountedPtr& operator=(const RefCountedPtr<Y>& other) {
+    // Note: Order of reffing and unreffing is important here in case value_
+    // and other.value_ are the same object.
+    if (other.value_ != nullptr) other.value_->IncrementRefCount();
+    if (value_ != nullptr) value_->Unref();
+    value_ = other.value_;
+    return *this;
+  }
 
   ~RefCountedPtr() {
     if (value_ != nullptr) value_->Unref();
   }
 
   // If value is non-null, we take ownership of a ref to it.
-  void reset(T* value = nullptr) {
+  template <typename Y>
+  void reset(Y* value) {
     if (value_ != nullptr) value_->Unref();
     value_ = value;
   }
 
+  void reset() {
+    if (value_ != nullptr) value_->Unref();
+    value_ = nullptr;
+  }
+
   // TODO(roth): This method exists solely as a transition mechanism to allow
   // us to pass a ref to idiomatic C code that does not use RefCountedPtr<>.
   // Once all of our code has been converted to idiomatic C++, this
@@ -89,16 +124,34 @@ class RefCountedPtr {
   T& operator*() const { return *value_; }
   T* operator->() const { return value_; }
 
-  bool operator==(const RefCountedPtr& other) const {
+  template <typename Y>
+  bool operator==(const RefCountedPtr<Y>& other) const {
     return value_ == other.value_;
   }
-  bool operator==(const T* other) const { return value_ == other; }
-  bool operator!=(const RefCountedPtr& other) const {
+
+  template <typename Y>
+  bool operator==(const Y* other) const {
+    return value_ == other;
+  }
+
+  bool operator==(std::nullptr_t) const { return value_ == nullptr; }
+
+  template <typename Y>
+  bool operator!=(const RefCountedPtr<Y>& other) const {
     return value_ != other.value_;
   }
-  bool operator!=(const T* other) const { return value_ != other; }
+
+  template <typename Y>
+  bool operator!=(const Y* other) const {
+    return value_ != other;
+  }
+
+  bool operator!=(std::nullptr_t) const { return value_ != nullptr; }
 
  private:
+  template <typename Y>
+  friend class RefCountedPtr;
+
   T* value_ = nullptr;
 };
 
@@ -107,11 +160,6 @@ inline RefCountedPtr<T> MakeRefCounted(Args&&... args) {
   return RefCountedPtr<T>(New<T>(std::forward<Args>(args)...));
 }
 
-template <typename Parent, typename Child, typename... Args>
-inline RefCountedPtr<Parent> MakePolymorphicRefCounted(Args&&... args) {
-  return RefCountedPtr<Parent>(New<Child>(std::forward<Args>(args)...));
-}
-
 }  // namespace grpc_core
 
 #endif /* GRPC_CORE_LIB_GPRPP_REF_COUNTED_PTR_H */